The present invention relates to an image displaying technique that converts an analog video signal to a digital video signal to display an image.
Image displaying devices, which use a fixed pixel device such as a plasma display panel (PDP) or a liquid crystal display panel (LCD), generally have low contrast compared to image displaying devices that use a cathode-ray tube. Conventional measures to improve contrast in PDPs include at least a technique for increasing the light-emitting efficiency of phosphor and a technique for improving control of the panel. They are described in detail, for example, in Japanese Patent Application Laid-Open No. Hei 10-208637 and Japanese Patent Application Laid-Open No. Hei 8-138558. An example of a technique for adjusting video contrast in a television receiver includes the technique described in Japanese Patent Application Laid-Open No. Hei 4-10784. Japanese Patent Application Laid-Open No. Hei 4-10784 describes a technique in which the maximum value, the minimum value, and the mean of a digital signal is converted from a video signal before storing the values. Based on the result of the detection and calculation, amplification of the video signal is performed to improve contrast.